1. Field of the Invention
The invention relates to a process for removing a composite coating present on the body of a gas bottle used to store pressurized gas so that the body of said gas bottle may subsequently be recycled.
2. Related Art
Generally, there are four types of gas bottle used for storing gas, namely:
type I bottles, which are bottles made entirely of metal (steel or aluminum);
type II bottles, which are bottles consisting of a metal (steel or aluminum) body coated with a composite, KEVLAR/epoxy for example;
type III bottles, which are bottles consisting of an aluminum body, of smaller thickness than the bodies of type I and II bottles, coated with a composite, for example made of KEVLAR/epoxy; and
type IV bottles, which are bottles consisting of a blow-molded polyethylene or polyamide body coated with a composite.
The advantage of type II and III bottles lies in the fact that the bottles, while retaining the same mechanical properties as type I bottles, are lighter. Type IV bottles are used in very specific cases. Type II and III bottles have a metal body, called a liner, in which the gas is stored, surrounded by a composite “skin”.
However, European environmental standards are increasingly strict and now require that products are designed to be recycled. These bottles are thus currently recycled in the following way.
Firstly, the bottle is cut into two parts and, on the one hand, the metal is recovered and, on the other hand, the composite is recovered and ground up.
However, cutting the metal liner into two half-bottles does not allow the liner to be directly recycled as a gas container. It is only recycled as a base metal that needs to be remelted and reformed to manufacture new liners. Therefore, at the present time the recycling operation is not optimized.
The problem to be solved is thus to provide a process that allows effective and ecological recycling of gas bottles, in particular type II and III bottles, i.e. gas bottles consisting of a composite-coated metal body or liner, which process does not require the bodies of the used bottles to be cut into two for the composite coating to be removed from their surface, and consequently allows said used bottle bodies to be reused without subsequent remelting and reforming.